Recently, display devices for uses in mobile devices are increasingly strongly desired to have higher definition and consume less power. Examples of display devices for uses in mobile devices are liquid crystal display devices (LCDs), display devices using light emitting elements, for example, organic light-emitting diode (OLED) display devices, electronic paper display devices, and the like.
Organic light-emitting diode display devices and electronic paper display devices, among the above, do not require a backlight unit or a polarization plate, which is required in liquid crystal display devices. These display devices are a target of attention as thin light emitting display devices consuming low power. Especially, top emission-type organic EL display devices using white light emitting elements and color filters for light emission to realize full-color display have been progressively developed. Such top emission-type organic EL display devices realize both of a higher numerical aperture of pixels and higher definition, and therefore attract a significant attention.
It is known regarding a high-definition top emission-type organic EL display device that in the case where the distance between a light emitting layer and a counter substrate is different among a plurality of pixels, non-uniform display is caused by a difference in the optical path length. In order to suppress the non-uniform display, a technology of locating spacers between an array substrate having a light emitting layer and a transistor layer formed thereon, and the counter substrate, has been developed (e.g., Japanese Laid-Open Patent Publication No. 2006-252988). In the case where the spacers have a height equal to, or larger than, the thickness of a filler located between the array substrate and the counter substrate, the distance between the array substrate and the counter substrate is controllable by adjusting the height of the spacers.
In the meantime, when the filler located between the array substrate and the counter substrate is thick in a high-definition display device, there occurs a problematic phenomenon that light emitted from the light emitting layer passes an adjacent pixel to be output outside (light leak between adjacent pixels). Especially in a structure in which color filters are located on the side of the counter substrate, colors are mixed due to the light leak between the adjacent pixels. In order to suppress such color mixing, the distance between the light emitting layer and the color filters needs to be shortened. For example, a structure of using partitions demarcating the pixels and a filler as spacers, instead of using conventionally used spacers, has been developed. In the case of this structure, the spacers and the filler located on the spacers are held between the array substrate and the counter substrate. The height of the spacers and the thickness of the filler need to be controlled to be uniform in a planar direction of the substrates.